This invention relates in general to an apparatus for determining distance coordinates, and more particularly to an apparatus for determining distance coordinates representative of the position of a cursor on a screen of a display unit of a computer system, for example.
A mouse is a device for determining distance coordinates for a computer system, where the coordinates represent the position of a cursor on the screen of a display unit of the computer system.
In a mechanical mouse, forward and backward and lateral motion of a roller ball over a pad having sufficient friction to assure rotation of the ball is converted by a mechanical mechanism into x and y equivalent mechanical translations. The mechanical translations are then converted into proportional x and y electrical signals which are fed by a cable to the display unit to serve as cursor-positioning input signals for the display.
Mechanical mouse devices incorporate moving parts that can wear out. The roller ball mechanism also requires periodic cleaning to remove accumulated dirt and to prevent internal malfunctioning.
An optical mouse device is an improvement over the conventional mechanical mouse device. In an optical mouse, forward and background and lateral motion takes place over a specially prepared pad having some characteristic such as an orthogonal array of fine reflecting lines which enables optical signal illumination of the pad by the mouse and subsequent processing of the reflected optical signal to provide cursor-positioning input signals for the display.
Although the optical mouse benefits by the absence of moving parts, it still requires a specially prepared pad that needs care and maintenance.